Gear & Gadgets —

Motherboard ills leave AMD users with Phenomenal headache

AMD's 780G chipset has earned good reviews across the board, but poor …

Various news sources have been pouncing on AMD's acknowledgment of potential problems when a high-end Phenom X4 processor is paired with certain 780G motherboards, but some of these articles have been focusing on the wrong part of the equation. The reported overheating and stability issues aren't being caused by Phenom, but by motherboard manufacturers' failure to design/certify their solutions for a Phenom processor with a 125W TDP.

This type of issue actually isn't all that rare; a $49 motherboard is $49 for a reason. Even if the motherboard's chipset is technically capable of running a high-end processor, the motherboard may not be designed to handle the CPU's power draw and thermal output. That's essentially what has happened here, but a combination of other factors has made the situation more important than it might otherwise be.

The errant motherboards, in this case, aren't no-name knock-offs from mainland China or seventh-tier OEMs. These are boards from ASUS, Gigabyte, and ECS, with prices, in some cases, in the $90-$100 range. The 780G chipset that these boards are based on, meanwhile, is easily the strongest product in AMD's current platform portfolio. The HD 3000 series from ATI might be price/performance competitive with NVIDIA cards, and Phenom might be a reasonable Intel alternative, but the 780G chipset positively shines against its integrated Intel competition. AMD technically classifies the 780G as a mainstream chipset, but for many people its low power consumption, newer southbridge, and excellent integrated graphics performance make it a more appealing than the "enthusiast" 790FX.

Motherboard manufacturers are, of course, free to design their products to support any CPU grades that they please, but ECS, Gigabyte, Asus, and Biostar have apparently made almost no effort to communicate the limitations of their respective 780G products to consumers. I searched written (motherboard manual) and online (web site) material on a total of seven 780G motherboards made by ECS, ASUS, Biostar, Sapphire, and Gigabyte, to see what CPU specifications the board manufacturers had set.

Written Documentation: None of the seven boards I investigated listed specific processor support. The three ASUS boards (M3A-H, M3A78-EMH, and M3A78-EH) and the Gigabyte GA-MA78GM-S2H all claim to support both Phenom and Phenom FX processors. The latter is interesting, considering that AMD has never released such a product, but it seems to be indicative of how motherboard manufacturers approach the issue. Biostar, Sapphire, and ECS don't claim to support Phenom FX, but make no mention of incompatible Phenom processors.

Online CPU support list: Here, the available data was much better. Of the manufacturers we checked, only Sapphire failed to provide any sort of CPU support page. Information from the other manufacturers corroborated the 125W issue. The ECS A780GM-A and Gigabyte GA-MA78GM-S2H both can handle up to a Phenom 9750, while the Asus M3A78-EMH, M3A78-EH, and Biostar TA780G only support up to the Phenom 9600 (and presumably 9650). Of these seven boards, only one of them—the ATX form-factor Asus M3A-H—officially supports Phenom 9850 at this time. CPU specification information, however, is only listed on the CPU Support page. Neither the listed board specifications at NewEgg nor the board specifications listed at the manufacturer's page make any mention of limited CPU support or signal a problem with 125 TDP processors.

Either better documentation or better implementation would've solved this problem before it occurred. According to AMD, affected motherboard manufacturers may release BIOS updates to improve processor support, but some of the boards in question are literally incapable of handling a 125W processor. For now, if you intend to build on 780G and want a Phenom X4 9850, the ASUS M3A-H is a confirmed safe bet. Buy anything else, and you invoke the ancient rule of caveat emptor.